A core material with a fiberglass or glass wool may be used as the core material for vacuum insulator only after the pre-treatment thereof. This is because the fiberglass and glass wool have a shape like a fiber, and when they are used as they are, they may be easily deformed by an external force, or may be slipped between the fibers. Therefore, a compression process, such as a needling process, is carried out, as well as an organic or inorganic binder is used to prevent the slipping of the fibers.
However, the organic or inorganic binder may destabilize the performance of the vacuum insulator, and certain components of gases are to be leaked to the outside from the organic or inorganic binder at the time of using with the vacuum insulator. These gases may cause to drop the degree of vacuum inside the vacuum insulator, which therefore degrades an insulation performance.
In addition, in the case of the fiberglass or glass wool, it is difficult to re-use and burn at the time of the disposal thereof, and the materials themselves weigh a lot and a large amounts of dusts may be blown in the process of manufacturing the vacuum insulator.